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Thread: Fire block caulk around pipes - where and what kind?

  1. #1
    DIY Member techinstructor's Avatar
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    Question Fire block caulk around pipes - where and what kind?

    I have questions as to where fire block caulk is required around pipe penetrations. Can someone answer yes or no to the following locations:

    * joists?
    * blocking (between joists, over basement load-bearing wall)?
    * subfloor (from basement to 1st floor and/or 1st floor to attic)?
    * sheathing for roof?

    My next question concerns compatibility with Pex. I have 3M Fire Block caulk. It was recommended by the salesman at the plumbing store (not a big box store) as what the plumbers use.

    Viega Pex says this in their literature:

    When penetrations must be sealed for air infiltration purposes, there are several options available. A good grade of silicone, acrylic, or siliconized acrylic caulking (DO NOT use oil-base caulks), most of the canned expanding foams, and open- or closed-cell pipe insulation are good sealing materials and may be used in direct contact with PEX tubing. .... There are a number of fire stopping compounds readily available that have been listed for use with PEX tubing. These compounds come in standard caulking tubes and are identified as waterbased, acrylic or latex. Consult the compound manufacturers’ instructions for proper application.
    I can't find any list of these fire stopping compounds at the Viega site and the 3M Fire Block doesn't say any of these three words, "waterbased, acrylic or latex." I guess I could call Viega and/or 3M to find out more. If the 3M isn't compatible, does anyone have a suggestions as to what will work with both Pex and PVC (my DWV piping)?

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    I'm bumping this in hopes of getting a response. If you're not familiar with the 3M product, I'd still like to know what you use as fire stop sealant that is compatible with Pex. I can check with my inspector as to where it has to be applied.

    Thanks

  3. #3
    Plumber jimbo's Avatar
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    Here is some 3m info. I note that some of them say not for CPVC, but don't mention PEX


    for pex: http://multimedia.3m.com/mws/mediawe...vTSevTSeSSSSSS--
    Last edited by jimbo; 10-11-2011 at 04:38 PM.

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    Quote Originally Posted by jimbo View Post
    Here is some 3m info. I note that some of them say not for CPVC, but don't mention PEX


    for pex: http://multimedia.3m.com/mws/mediawe...vTSevTSeSSSSSS--
    Jimbo, I'm getting an error message when I click on the link. Can you try pasting it again?

    I found a document on the 3M site concerning CPVC, but like you I couldn't find anything specifically addressing Pex. I'm still looking for information.

    Thanks

    try this: http://solutions.3m.com/wps/portal/3...beTGS9R7QM25gl

    If the forum somehow blockse the link, just google 3m fire barrier sealants
    Jim
    Last edited by jimbo; 10-12-2011 at 06:06 AM.

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    DIY Member bsperr's Avatar
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    I've used the Great Stuff fireblock spray foam, and I think it's easier to apply than caulk (especially in tight places). The safety data sheet doesn't mention any incompatibility with pex.

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    Default Update on fire block

    I called Viega today and asked them about the caulk. They emailed me a short list of fire block/barrier sealants that are compatible with Pex. I'm attaching it here in case it could be of help to someone else. TA PEX firestops_1010.pdf I also found that this 3M product is sold at Lowes.

    BTW, the Viega tech support rep told me that the Great Stuff fire block foam was NOT compatible and should not be used with Pex.

    The whole issue of compatibility of materials seems to get more and more complicated as people use more and more artificial substances and the formulas get changed/improved in order for products to remain competitive. It's frustrating for the consumer and I'm sure it must also be frustrating for the manufacturer and the installers as well.

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    DIY Member bsperr's Avatar
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    "BTW, the Viega tech support rep told me that the Great Stuff fire block foam was NOT compatible and should not be used with Pex."

    That's good to know. I've never run pex before, but I'll make sure not to use that foam.

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